<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Offscreen</title>
</head>
<body>
    <textarea id="text"></textarea>
    <iframe id="theFrame" src="sandbox.html" style="display: none"></iframe>
</body>
</html>